As you well know, you can't get the loop to fade out automatically over time. Not with a boomerang alone. It will lower the volume of a sample if you you lay something new over it (using the Stack button), but that's just to make space for the new layer while the loop itself plays endlessly at the same volume. Have you tried branching your sound where one branch of the fresh noise is going to one output the other branch feeds into the boomerang, then feeding the boomerang through a plain old volume pedal? By pressing the little chrome tap button at the top of the boomerang you can set it to play back only the echo and filter out the new sounds coming in. This way you can control just the boomeranged effects. It's low-tech, I know. But you can do it for the cost of a cheap volume pedal. For free, using the setup above you can also adjust that volume roller on the left side of the Boomerang while it's looping and do the same thing, if less accurately. Because to do what you want to do you'd need either (1) a midi-controllable or automated mixer or similar device that's set to lower the volume in increments which correspond to the loop length on your boomerang, which is a dubious if not impossible venture, or (2) a looper with a similar delay time that's either midi controllable or is degenerative. In either case, for the same money you might as well just use an Echoplex DP. Let me know what you end up doing... ---original message--- My question seeks a recommendation on how to get the Boomerang to act regenerative, (or degenerative) as the more expensive Echoplex might. I've thought of getting a Boss DD-5 delay stompbox (or similar) and trying to set regen to various settings. What I want to do is have a real-time variable regen factor using some kind of foot pedal (as my hands are "in the beams". Thanks in advance for your help..